Screw die-head



Dec. 11, 1945.

A. E. HECKMAN SCREW DIE-HEAD Filed Juhe 13, 1944 2 Sheets-Sheet 1 INVENTOR A0005? f/vz'c/mwm/ 7 ATTO RNEYS 1945- A. E. HECKMAN I SCREW DIE-HEAD Filed June 13, 1944 2 Sheets-Sheet 2 Ffz'ca5.

I vIii- 36. Z5 2 39 27 y 30 24 INVENTO R AUGUST .5 HECKMAA/ 20 1 -25 H a Z5 a m avs I Patented Dec.11, 1945 UNITED STATES PATENT OFFICE.

SCREW DIE-HEAD August E. Heckman, Seaford, N. Y. 7 Application June 13, 1944, Serial No. 540,077 6 Claims. (01.10-116) This invention relates to a screw thread cutting die-head which is automatically releasable and self-opening and automatically closing, andhas especial reference to a screw thread cutting diehead which may be used in automatic and other types of lathes. V

' More particularly the die-head of the present invention is of the type disclosed in my copending application, Serial No. 508,733, filed November 2, 1943, issued as Patent No. 2,357,739, September 5,1944.

An object of the present invention is the pro- Vision of a die-head of the indicated character embodying improvements whereby the thread cuttin die sections may be closed in proper relation for ready cutting of the threads, and which sections will open and be disengaged from the cut threads to permit ready withdrawal from the Work.

A further object of the invention is the pro- Vision of improvements in a die-head of the character mentioned whereby the holder members or jaws of the thread cutting die sections are so constructed and arranged that said sections will move equally and in unison to the open and closed relationship. I

I A further object is the provision of improvements for releasably latching the thread cutting die sections so that they may operate under proper tension and so' that adjustments may be made to maintain the proper cooperative relation of the die sections to each other.

With the foregoing, other objects, Ibenefits and. advantages of the invention will appear when the following specification is read in connection with the accompanying drawings, in which,

Figure 1 is a side elevational view of a screw thread cutting die-head embodying the features of the invention upon a lathe.

Figure 2 is a front elevational view of the diehead per se, the same being shown closed.

Figure 3 is a side elevational View thereof.

Figure 4 is a view similar to Figure 3 but showing the die-head opemand portions being broken away to showcertain features.

Figure 5 is a longitudinal sectional view taken on the line 5-5 of Figure 3 and lookin in the direction indicated by the arrows. I

Figure 6 is a detail sectional view taken on' the line 6-6 of Figure 3 and looking in the direction indicated by the arrows.

Referring now more particularly to the drawings, it will be apparent ther is shown a screw thread cutting die-head Ill including die holding or supporting jaws or members I I and I2 substantially similar to each other. Each of the members II and I2 is rectangular in plan and somewhat wider than it i long. There is an inwardly projecting front portion I3 having a segmental seat I4; Each jaw II and I2 has inwardly projecting rear apertured lugs I5 in spaced relation to each other. The apertures in said lugs are in axial alinement. The jaws II and I2 are hingedly or pivotally mounted on a shank I6 having a circular abutment I7 and a diametrically disposed lug I8 on the abutment I1. The lug I8 fits between the lugs I5 of each jaw II and I2 when the lat ter are assembled with respect to said lug I8. Thus a pair of lugs I5 is disposed at each side of the lug I8 and the lugs I5 of each pairare on the jaws II and I2 respectively. A pivot IS in the form of a headless bolt extends through the lugs I5 of each jaw and the lug I8, said pivot- I9 being in threaded engagement with one of the lugs I5 and loose in the other lug I5 and the lug I8. In this manner the jaws I I and I2 are hinged 1y or pivotally connected for movement to open: and closed relation on axes extending at right angles to the longitudinalaxis of the shank I6. Suitable segmental screw the sections are secured in position on the seats I4 respectively of the jaws. Each section 20 is held in place by looking screws 2I driven into th related jaw with the heads of the screws 2| bearing on the section 20. The die sections 20 are complemental to each other and when the jaws I I and I2 are in the closed relation the die sections cooperate to provide a thread cutter concentric to the axis of the shank I6.

The jaws II and I2 are releasably held in the closed relation by a latching device presently to be described. A stud 22 is provided which consists of a portion 23 and a portion 24 eccentric to the portion 23. The portion 23 is smaller in diameter than the portion 24 and the axis of the former is olfset with respect to the axis of the latter. The portion 23 has a circular groove 25 therein, and said portion 23 is received in a bore in the jaw II. A set screw 26 carried by the jaw II projects into the groove 25 to hold the stud 22 in place. The portion 24 has a kerfed head 21. A trigger arm 28 has a. hole in its upper end to receive the stud' portion 24, and said end also has a recess 29 larger in diameter than the diameter of the portion 24 to accommodate a helical torsional spring 30 having one end in engagement with the jaw I I and its other end in engagement with the arm 28, as shown in Figure 6. The head '21 of the stud 22 engages the arm 28 to keep. it in pivotal connection with the portion 24. The spring 30 constantly urges the arm 28 to a latching position and is yieldable to allow said arm to be moved to a' releasing position. The lower end of the arm 28 has a case hardened abutment 3| secured thereto by screws 3'2. The abutment 3|, if desired, may be formed integral with the arm 28. A case hardened half round abutment pin 33 is secured to the jaw I2 so that the arm 28 and its abutment 3I may cooperate therewith to latch the jaws I I and I2 in the closed relation with the die Sections 20 in functioning relation for the thread cutting operation.

It will be understood that the spring 39 holds the arm 28 against the pin 33 while the abutment 3| engages said pin to latch the jaws II and I2 in the closed relation. A helical expansion spring 34 is arranged between the jaws with the opposite ends of the spring disposed in sockets respectively, a in the jaws. This spring 34 has a normal tendency to constantly urge the jaws to the open relation. The jaws are limited in their pivotal movement to the open relation by the abutment I! which the jaws engage. By turning the eccentric stud 22 as required the trigger arm 28 may be adjusted together with the abutment 3| with respect to the pin 33, thereby making it possible to vary the closed relation of the jaws and their die sections .20. Thus the die sections 20 may be adjusted to make a first rough cut thread and then a fine or finish cut thread.

In order that the jaws I I and I2, and therefore the die sections 20, move equally and in unison to the open and closed relation, there are provided intermeshing gear teeth 35 and 36 on the lugs respectively of the jaws. The lugs I5 with their teeth function as gear sectors. Thus the die sections will be closed in proper relation for ready cuttin of the threads, and also will open and bedisengaged from the cut threads to permit ready withdrawal from the work.

The die-head hereinabove described is shown in use in an automatic lathe by way of example. The lathe 40 includes a bed 4 I, a fixed head stock 42, and a sliding head stock 43. The shank I 5 of the die-head II! is clamped to the head stock 43 by a clamp 44. A piece of work 45, such as a pipe, rod, or other cross-sectionally round stock tobe externally screw threaded is carried by a chuck 46 on the head stock 42, the work 4-5 and the shank I6- being coaxial. Consequently, the die sections 20 in the closed relationship will be ccaxial to the work for the thread cutting operation, Slidably adjustable along the bed 41 is a stop 41 in the pathof the abutment 31 on the arm 28'. The position of the stop 41 determines the. length of the portion of the work to be threaded.

With the disposition of the parts shown in Figure 1, whenthe die-head Ill is closed, th head stock 43 is slid along the bed. 4 I. toward the work 45 which is being rotated, by the driven chuck 45. As the die sections 20 engage the-end of the work 45- the thread cutting commences and continues until the abutment 3I- encounters the stop 41, whereupon the abutment 3t will be disengaged from the pin 33. and the arm 28 will be swung backwardly onits. pivot 22.. The spring; 3.4 immediately causes the jaws- I I and I2v to open, thereby disengaging the die sections 20, from the work and so permitting the ready withdrawal of. the die-head l8. Upon return movement of the diehead In by the head stock 43 the jaws I I- and- I2 maybe closed and latched manually-or by means incorporated in the. lathe for that purpose, preparatory to the next threading operation.

While I have shown and described what I consider to be the most practical embodimentof' my invention, I wish it understood thatlsuch changes in construction. and design as. come within the scopeof the appended, claims may be resorted to if desired without. departing. from they spirit of my invention.

Having thus, described the. invention what I claim as new and desire: to secure by Letters Patent of the United Statesisr 1. In a die-head, the combination of pivotally connected die supporting jaws, resilient means constantly acting on said jaws and having a normal tendency to move said jaws to open relation with respect .to each other, and a device to releasably retain said jaws in a closed relation, said device including a fixed abutment on one of said jaws, a trigger, a pivot consisting of eccentrically related portions integral with each other, the first of said portions secured to one of said jaws, the second of said portions engaged with said trigger, said trigger thus being mounted for pivotal movement and also being adjustable, said trigger being releasably engageabl with said abutment, and resilient means coacting with said trigger to keep the trigger under suitable tension while it is engaged with said abutment.

I 2. In a die-head, the combination of companion die supporting jaws, spaced pairs of lugs on said jaws, a shank, a pivot extending through-the lugs of each jaw and a portion of the shank to connect each jaw for pivotal movement to openand closed position, and gear teeth on the lugs of one jaw which mesh with teeth on the lugs of the other jaw to cause the jaws to. move in unison in response to pressure exerted on either of said aws.

3. In a die-head, the combination of pivotally connected die supporting jaws, resilient means constantly acting on said jaws and having a normal tendency to move said jaws to open relation with respect to each other, and a device to releasably retain said jaws in a closed relation, said device including a fixed abutment on one of said jaws, a trigger, means mounting said trigger on the other of said jaws for pivotal movement and also for adjustment, said trigger being releasably engageable with said abutment, and resilient means coacting with said lastlmeaiis to constantly keep said trigger under suitable tension while the trigger is engaged with said abutment.

4. In a die-head, the combination of pivotally connected die supporting jaws, resilient means constantly acting on said jaws and having anormal. tendency to move said jaws to open relation with respect to each other, and. a device to releasably retain said jaws in a closed relation, said device including a. fixed abutment on on of said jaws, a trigger, and means mounting saidtrigger on the other of said jaws for pivotal movement and also for adjustment, said trigger being releasably engageable with saidv abutment, said last means consisting of a pivot composed of eccentrically related portions integral with. each other, one of said portions secured tothe'related die supporting jaw and theother portion engaged with said trigger.

. 5. In a die-head. having d-ie supporting; laws which are opened by spring action, a. latching device cooperating with: saidejawsto releasably latch them in the closed relation; said device includinga, trigger arm, an eccentric stud. on one of said jaws providing an adjustable pivot for said trigger arm, and. means: to resiliently urge: said trigger arm to the latching position.

6. In a die-head, the combination of hingedly connected die supporting jaws, and coacting means on said jaws-to cause one jaw to moveto open" and closed position. in. response to corresponding movementof theother jaw, so'thatboth jaws, will move equally and in unison, saidv coacting means comprising inter-meshing gear sectors; i

, AUGUST E: 

